Pandion haliaetus melvillensis Mathews
Osprey
Pandion haliaëtus melvillensis Mathews, Australian Avium Rec., 1, 1912, p. 34. (Type locality, Melville Island.)
Pandion leucocephalus Finsch, Journ. Mus. Godeffroy, 8, 1875, p. 49 (Palau).
Pandion haliaetus leucocephalus Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 1 (Pelew).
Pandion haliaëtus cristatus Kuroda, in Momiyama, Birds Micronesia, 1922, p. 40 (Pelew); Hand-list Japanese Birds, rev., 1932, p. 182 (Pelew); Hand-list Japanese Birds, 3d ed., 1942, p. 203 (Palau).
Pandion haliaëtus melvillensis Mayr, Birds Southwest Pacific, 1945, pp. 55, 286 (Palau); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 46 (Guam, Palau).
Geographic range.—Malaysia, northern Australia, Melanesia. In Micronesia: Mariana Islands—Guam; Palau Islands—Peleliu.
Remarks.—The Osprey was first recorded at Palau by Finsch (1875:49). The author (1948:46) cites records obtained by C. K. Dorsey at Peleliu in 1944 and 1945. Dorsey saw the Osprey on several occasions; the NAMRU2 party did not find the bird while on their stay there in August and September, 1945. B. V. Travis of NAMRU2 saw an Osprey at Agaña Bay, Guam, in December, 1945. He observed the bird to be carrying a fish in its talons. Flavin observed the Osprey at Guam on January 28, 1945, and on December 23, 1945. Mayr (1945a:286) says that the Osprey apparently breeds at Palau. The bird seen in the Marianas may have been P. h. haliaetus (Linnaeus), a visitor from Asia, which is known to winter in the Philippines and adjacent areas.
The Osprey is the only resident member of the order Falconiformes, and it is principally a fish eater. The few records of mammal and bird eating hawks in Micronesia indicate that predation on insular vertebrate populations from this source is at a minimum. The absence of this predation may have a pronounced effect on the resident land birds, particularly from the standpoint of the perpetuation of nonadaptive mutations, which might be "weeded out" under what might be considered as normal predatory pressure in continental bird populations.